FRANCE - An acoustic device to scare away sea bream causing damage to mussel and oyster stocks has been developed by the French Research Institute for Exploitation of the Sea (Ifremer).
Seabream can cause considerable damage to mussels and oyster shells which it crushes with its powerful teeth, and for several years French shellfish producers have observed sudden large predations of their farms.
As part of the predator project, started in 2013, the experimental prototype of acoustic repellent from Ifremer was tested in 2013 and 2014 for five months in Rade de Brest and Bay Quiberon.
The repellent has shown effectiveness on large shoals of bream and an industrial project could emerge soon.
"The pingers existed to scare cetaceans, such as the device CETASAVER partly developed at Ifremer intended to keep dolphins during fishing operations, but not for the target species of fish, such as bream," explained Yves Le Gall, Head of Underwater Acoustic and Eric Menut, electronics engineer at Ifremer Brittany Centre.
This carnivore species can exceed 70 cm in length and weigh 8 kg. In the past, nets and screens have been used as protection from predation, which work in some cases but are expensive, fragile and require a lot of labour because they must be cleaned regularly.
The prototype acoustic repellent operates on low power and is estimated to work inside a range of between 200 and 300 metres.
The predator project also aims to improve knowledge on the biology and behaviour of seabream.
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